Sanders, Walter R. (1922). Ice Delivery. Chicago: Nickerson & Collins. pp. 170–172.
gmuender-tagespost.de
"Ein PS für 160 Blumenkübel" [One horsepower for 160 flower pots]. Gmünder Tagespost (in German). 31 July 2015. Archived from the original on 11 December 2019. Retrieved 25 February 2022.
"Twenty Mule Teams". Death Valley National Park. National Park Service. Retrieved 6 February 2013.
openlibrary.org
Smith, D.J.M. (1988). A Dictionary of Horse Drawn Vehicles. J. A. Allen & Co. Ltd. ISBN0851314686. OL11597864M.
Stratton, Ezra M. (1878). The World on Wheels; or, Carriages, with their Historical Associations from the Earliest to the Present Time, Including a Selection from the American Centennial Exhibition. New York: The author. OCLC3570369. OL7004294M.
Burt, Olive W. (1962). John Wanamaker: Boy Merchant. New York: Bobbs-Merrill. p. 62. OL5855211M.
"Ein PS für 160 Blumenkübel" [One horsepower for 160 flower pots]. Gmünder Tagespost (in German). 31 July 2015. Archived from the original on 11 December 2019. Retrieved 25 February 2022.
Stratton, Ezra M. (1878). The World on Wheels; or, Carriages, with their Historical Associations from the Earliest to the Present Time, Including a Selection from the American Centennial Exhibition. New York: The author. OCLC3570369. OL7004294M.